Image display apparatus and image display method

ABSTRACT

An image display apparatus according to an embodiment of the present invention includes: a moving unit configured to move a display position of an image displayed on a display screen; a setting unit configured to set a compressed image display area in the image; and a compression unit configured to, when a nondisplay area that is not displayed on the display screen is created in the image by the moving unit, compress the nondisplay area so that the nondisplay area fits within the compressed image display area and is displayed on the display screen.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. Pat. No. 8,259,133 filed Jul.8, 2008, which claims the benefit of and priority to JapaneseApplication No. 2007-181326 filed Jul. 10, 2007, the contents of each ofwhich are hereby incorporated by reference herein in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image display apparatus and an imagedisplay method, and, more particularly, to a technique for displaying amoved image.

2. Description of the Related Art

In recent years, there have been increased opportunities for displayingdata for third parties using a large screen display in a meeting orpresentation. For example, various types of data such as textual data,table data, and graphical data, which are created using applicationsoftware for a personal computer, are displayed for third parties usinga large screen display such as a front projector or a rear projector. Insuch a case, a multi-screen display function of displaying a pluralityof images, which are sent from different personal computers or from apersonal computer and a video apparatus, at the same time can beeffectively used.

The multi-screen display function is used in television sets. Asillustrated in FIG. 11, using the multi-screen display function, a firstscreen 110 of full screen size and a second screen 120 of reduced sizewhich is reduced so that the second screen 120 fits within apredetermined area can be displayed. However, in the case of a generalmulti-screen display function, as illustrated in FIG. 11, since thesecond screen 120 is displayed in front of the first screen 110, aportion of the first screen 110 under the display area of the secondscreen 120 is hidden and invisible.

In order to improve a visual effect by arranging important imageportions of a plurality of displayed screens, it is desirable that thedisplay areas of the first screen 110 and the second screen 120 befreely movable. For example, Japanese Patent Laid-Open No. 6-30335discloses a display method of moving a first screen so as not to overlapwith a second screen.

In the method disclosed in Japanese Patent Laid-Open No. 6-30335, a timeof Lm is added to a data writing time at which data is written into amemory so as to determine a data reading time at which the data is readout from the memory as illustrated in FIG. 12, so that a displayed imageis shifted to the left as illustrated in FIG. 13. On the other hand, bysubtracting the time of Lm from the data writing time so as to determinethe data reading time, the displayed image can be shifted to the rightas illustrated in FIG. 14.

However, since the image displayed after a display position has beenmoved extends off a screen area, a part of the image becomes invisible.Accordingly, it is difficult to see the entire area of the image. Inorder to see the entire area of the image, a method of compressing theimage so as to fit the entire area of the image within a limited displayarea that has been changed in accordance with the movement of thedisplay position can be considered. However, in this case, the aspectratio of the image is changed, or a part of the image the detailed viewof which is required is also reduced in size. This makes it difficult tosee displayed information.

SUMMARY OF THE INVENTION

The present invention provides an image display apparatus and an imagedisplay method which are capable of displaying all the informationcontained within an image without making it difficult to see theinformation.

An image display apparatus according to an embodiment of the presentinvention includes: a moving unit configured to move a display positionof an image displayed on a display screen; a setting unit configured toset a compressed image display area in the image; and a compression unitconfigured to, when a nondisplay area that is not displayed on thedisplay screen is created in the image by the moving unit, compress thenondisplay area so that the nondisplay area fits within the compressedimage display area and is displayed on the display screen.

An image display control method according to an embodiment of thepresent invention is a method of controlling an image display apparatus.The image display control method includes: moving a display position ofan image displayed on a display screen of the image display apparatus;setting a compressed image display area in the image; and compressing,when a nondisplay area that is not displayed on the display screen iscreated in the image, the nondisplay area so that the nondisplay areafits within the compressed image display area and is displayed on thedisplay screen.

According to an embodiment of the present invention, a part of an imagewhich extends off a compressed image display area is compressed so thatthe part fits within the compressed image display area and is displayedon a display screen. Accordingly, all the information contained withinthe image can be displayed without making it difficult to se theinformation. As a result, display flexibility can be improved.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a block diagram schematically illustrating an exemplaryconfiguration of an image display apparatus according to a firstembodiment of the present invention.

FIG. 2 is a diagram illustrating a display example of a screen accordingto the first embodiment of the present invention when the screen ismoved to the left.

FIG. 3 is a diagram illustrating an operation key according to the firstembodiment of the present invention.

FIG. 4 is a diagram illustrating an example of the time at whichwriting/reading of data in/from a memory according to the firstembodiment of the present invention is performed.

FIG. 5 is a diagram illustrating a display example of a screen accordingto a second embodiment of the present invention when the screen is movedto the right.

FIG. 6 is a diagram illustrating an example of the time at whichwriting/reading of data in/from a memory according to the secondembodiment of the present invention is performed.

FIG. 7 is a diagram illustrating a display example of a screen accordingto a third embodiment of the present invention when the screen isupwardly moved.

FIG. 8 is a diagram illustrating an example of the time at whichwriting/reading of data in/from a memory according to the thirdembodiment of the present invention is performed.

FIG. 9 is a diagram illustrating a display example of a screen accordingto a fourth embodiment of the present invention when the screen isdownwardly moved.

FIG. 10 is a diagram illustrating an example of the time at whichwriting/reading of data in/from a memory according to the fourthembodiment of the present invention is performed.

FIG. 11 is a diagram illustrating a display example of a screen using amulti-screen display function in the related art.

FIG. 12 is a diagram illustrating an example of the time at whichwriting/reading of data in/from a memory is performed in screen displayposition movement in the related art.

FIG. 13 is a diagram illustrating a display example of a screen inscreen display position movement in the related art.

FIG. 14 is a diagram illustrating an example of the time at whichwriting/reading of data in/from a memory is performed in screen displayposition movement in the related art.

FIG. 15 is a block diagram illustrating an exemplary hardwareconfiguration of a multi-window system in an image display apparatusaccording to a fifth embodiment of the present invention.

FIG. 16 is a block diagram illustrating a window processing sectionincluded in an image display apparatus according to the fifth embodimentof the present invention.

FIGS. 17A, 17B, and 17C are diagrams illustrating display examples of ascreen according to the fifth embodiment of the present invention whenthe screen is moved to the left.

FIG. 18 is a flowchart describing a window process according to thefifth embodiment of the present invention.

FIGS. 19A and 19B are diagrams illustrating display examples of a screenaccording to a sixth embodiment of the present invention.

FIGS. 20A and 20B are diagrams illustrating display examples of a screenaccording to the sixth embodiment of the present invention.

FIG. 21 is a flowchart describing a window process according to thesixth embodiment of the present invention.

DESCRIPTION OF THE EMBODIMENTS

Various embodiments of the present invention will be described belowwith reference to the accompanying drawings.

First Embodiment

FIG. 1 is a block diagram schematically illustrating an exemplaryconfiguration of an image display apparatus according to thisembodiment. Referring to FIG. 1, an image display apparatus according tothis embodiment includes an image signal input section 10, a scalingsection 20 for enlarging or reducing an input image, a frame memory 30,an image display section 40 including a display device and a driver forthe display device, a control section 50 for controlling an imagedisplay apparatus including the scaling section 20, and an operatingsection 60 for performing a control operation of the image displayapparatus. The scaling section 20 includes a reduction interpolationunit 21 and an enlargement interpolation unit 22.

If an input image is reduced, the reduction interpolation unit 21performs reduction interpolation processing upon image signalscorresponding to an input image by performing predetermined filteringbased on a reduction ratio controlled by the control section 50, andstores the image signals in the frame memory 30. The enlargementinterpolation unit 22 reads out the image signals stored in the framememory 30, and outputs the image signals to the image display section 40without processing them.

If an input image is enlarged, the reduction interpolation unit 21stores image signals corresponding to an input image in the frame memory30 without processing them. The enlargement interpolation unit 22 readsout the image signals stored in the frame memory 30, performsenlargement interpolation processing upon the image signals byperforming predetermined filtering based on an enlargement ratiocontrolled by the control section 50, and outputs the image signals tothe image display section 40.

If any of the reduction interpolation processing and the enlargementinterpolation processing are not performed, an input image is output tothe image display section 40 as same-magnification image signals. Eachof the reduction interpolation processing, the enlargement interpolationprocessing, and the writing/reading of data in/from the frame memory 30is performed under the control of the control section 50.

An input image (image signal) input from the image signal input section10 is digital data including a horizontal synchronization signal Hs, avertical synchronization signal Vs, and a pixel clock signal DCK.Writing of data in the frame memory 30 is performed in synchronizationwith these synchronization signals and the pixel clock signal. That is,each dot position (an address in the horizontal direction) is updated insynchronization with the pixel clock signal DCK, each scanning lineposition (an address in the vertical direction) is updated insynchronization with the horizontal synchronization signal Hs, and eachframe is updated in synchronization with the vertical synchronizationsignal Vs.

The reading of data from the frame memory 30 is performed insynchronization with a horizontal synchronization signal Hs2, a verticalsynchronization signal Vs2, and a pixel clock signal DCK2 which aregenerated by a reading synchronization signal generation unit (notillustrated) included in the scaling section 20. These readingsynchronization signals and the pixel clock signal are output to theimage display section 40, and are also used as synchronization signalsfor the display device therein. The scaling section 20 performs thereduction interpolation processing and the enlargement interpolationprocessing based on a data writing address and a data reading addresswhich are controlled by the control section 50.

Next, an image display method according to this embodiment will bedescribed with reference to FIGS. 2 and 3. First, a screen move mode isset by operating an operation key included in the operating section 60.In the screen move mode, a screen display position is moved inaccordance with the number of times the operation key is pressed, whichis illustrated in FIG. 3 and is included in the operating section 60, ora pressing duration of the operation key.

For example, as illustrated in FIG. 2, on an image display device(display screen) having Lh pixels in the horizontal direction and Lvpixels in the vertical direction, an image 111 having the same number ofpixels as the image display device is input. As illustrated using animage 112, a display position is moved to the left in the horizontaldirection by a distance Lml. That is, a nondisplay area having thelength of Lml in the moving direction of the image is generated. At thattime, an area of the image display device from the left end thereof to aposition apart from the left end by a distance Lcl in the horizontaldirection is set as a compressed image display area.

In this case, a part of the input image 111 in an area from the left endthereof to a position apart from the left end by a distance (Lcl+Lml) inthe horizontal direction is compressed for display so that the part fitswithin the area of the image display device from the left end thereof tothe position apart from the left end by the distance Lcl in thehorizontal direction. Accordingly, after the display position has beenmoved, in the area of the image display device from the left end thereofto the position apart from the left end by the distance Lcl in thehorizontal direction, an image obtained by compressing the part of theinput image 111 in the area from the left end thereof to the positionapart from the left end by the distance (Lcl+Lml) in the horizontaldirection at a compression ratio of Lcl/(Lcl+Lml) is displayed. If Lclis larger than Lml, image compression is performed using a compressionratio of (Lcl−Lml)/Lcl.

On the other hand, after the display position has been moved, in an areaof the image display device from the position apart from the left endthereof by the distance Lcl in the horizontal direction to a positionapart from the left end by a distance (Lh−Lml) in the horizontaldirection, a part of the input image 111 on the right side of theposition apart from the left end thereof by the distance (Lcl+Lml) inthe horizontal direction is displayed without being compressed. Afterthe display position has been moved, in an area of the image displaydevice on the right side of the position apart from the left end thereofby the distance (Lh−Lml) in the horizontal direction, for example, ablack blank image is displayed.

FIG. 4 is a diagram illustrating an example of the time at whichwriting/reading of data in/from the frame memory 30 according to thisembodiment is performed.

Referring to FIG. 4, Hs1 denotes an input horizontal synchronizationsignal, DCK1 denotes an input pixel clock signal, DATA1 denotes an inputimage signal, Hs2 denotes an output horizontal synchronization signal,DCK2 denotes an output pixel clock signal, and DATA2 denotes an outputimage signal.

If a display position is not moved in the horizontal direction, anaddress Whs corresponding to the number of pixel clocks between afalling edge of the input horizontal synchronization signal Hs1 and thestart of the effective image area of an input image is stored in theframe memory 30 as an input image signal functioning as a horizontaldata writing start address. Input image signals corresponding to thenumber of effective pixels are written in the frame memory 30 byincrementing the address Whs until a horizontal data writing address(Whs+Lh) is obtained.

At the time of reading of data from the frame memory 30, based on afalling edge of the output horizontal synchronization signal Hs2, ahorizontal data reading start address Rhs is set. The image signalscorresponding to the number of effective pixels are read out from theframe memory 30 by incrementing the address Rhs until a horizontal datareading address (Rhs+Lh) is obtained. Consequently, the input image canbe displayed on the entire area of the image display device.

If the display position is moved to the left by the distance Lml in thehorizontal direction, an address (Whs+Lml) obtained by adding thedistance Lml to the horizontal data writing start address Whs, which isa horizontal data writing start address in a case in which the displayposition is not moved, is set as a horizontal data writing startaddress. Subsequently, reduction interpolation processing is performedupon input image signals obtained in a period corresponding to the sumof the distance Lml and the distance Lcl functioning as the length ofthe compressed image display area in the horizontal direction (a part ofthe input image excluding a normal display area). Image signals arewritten in the frame memory 30 by incrementing the horizontal datawriting start address (Whs+Lml) by a value obtained by multiplying aposition in the input image by Lcl/(Lcl+Lml) until a horizontal datawriting address (Whs+Lml+Lcl) is obtained.

However, since a data writing address is an integer in reality, thehorizontal data writing start address (Whs+Lml) is incremented until thehorizontal data writing address (Whs+Lml+Lcl) is obtained. After aperiod corresponding to (Lml+Lcl) has elapsed from the start of theeffect image area of the input image, image signals are sequentiallyobtained by incrementing the horizontal data writing address(Whs+Lml+Lcl) until a horizontal data writing address (Whs+Lh) isobtained, and are then sequentially written in the frame memory 30.

At the time of reading of data from the frame memory 30, an address(Rhs+Lml) obtained by adding the distance Lml to the horizontal datareading start address Rhs, which is a horizontal data reading startaddress in a case in which the display position is not moved, is set asa horizontal data reading start address. Subsequently, image signalscorresponding to the number of effective pixels Lh are read out byincrementing the horizontal data reading start address (Rhs+Lml) until ahorizontal data reading address (Rhs+Lh+Lml) is obtained.

Consequently, a part of the input image 111 from the left end thereof tothe position apart from the left end by the distance (Lcl+Lml) iscompressed so as to obtain a compressed image, and the compressed imageis displayed in the compressed image display area of the length Lcl inthe display screen. Furthermore, a part of the input image 111 in anarea from the position apart from the left end thereof by the distance(Lcl+Lml) to a position apart from the left end by the distance Lh isdisplayed in the normal display area of the display screen from theposition apart from the left end thereof by the distance Lcl to theposition apart from the left end by the distance (Lh−Lml). In the areaof the display screen from the position apart from the left end thereofby the distance (Lh−Lml) to the position apart from the left end by thedistance Lh, a blank image is displayed.

Thus, if an image display position on a display screen is moved to theleft in the horizontal direction, a part of an image to be extended offthe display screen is compressed for display so that the part fitswithin a compressed image display area. As a result, all the informationcontained within the image can be displayed without loss of theinformation. In this embodiment, by operating a key included in theoperating section 60, a display position is moved. However, for example,if the image display apparatus includes an operating section including aremote controller, the movement of the display position may be performedby performing a key operation of the remote controller.

Second Embodiment

Next, an example illustrated in FIG. 5 will be described. In thisexample, on an image display device having Lh pixels in the horizontaldirection and Lv pixels in the vertical direction, the image 111 havingthe same number of pixels as the image display device is input. Asillustrated using an image 113, a display position is moved to the rightby a distance Lmr in the horizontal direction. The exemplary functionalconfiguration of an image display apparatus according to this embodimentis the same as that of an image display apparatus according to the firstembodiment, and the description thereof will be therefore omitted. Anarea of the image display device from the right end thereof to aposition apart from the right end by a distance Lcr in the horizontaldirection is set as a compressed image display area.

In this case, a part of the input image 111 in an area from the rightend thereof to a position apart from the right end by a distance(Lcr+Lmr) in the horizontal direction is compressed for display so thatthe part fits within the area of the image display device from the rightend thereof to the position apart from the right end by the distance Lcrin the horizontal direction. Accordingly, after the display position hasbeen moved, in the area of the image display device from the right endthereof to the position apart from the right end by the distance Lcl inthe horizontal direction, an image obtained by compressing the part ofthe input image 111 in the area from the right end thereof to theposition apart from the right end by the distance (Lcr+Lmr) in thehorizontal direction at a compression ratio of Lcr/(Lcr+Lmr) isdisplayed.

On the other hand, in an area of the image display device from theposition apart from the right end thereof by the distance Lcr in thehorizontal direction to a position apart from the right end by adistance (Lh−Lmr) in the horizontal direction, a part of the input image111 on the left side of the position apart from the right end thereof bythe distance (Lcr+Lmr) in the horizontal direction is displayed withoutbeing compressed. In an area of the image display device on the leftside of the position apart from the right end thereof by the distance(Lh−Lmr) in the horizontal direction, for example, a black blank imageis displayed.

FIG. 6 is a diagram illustrating an example of the time at whichwriting/reading of data in/from the frame memory 30 according to thisembodiment is performed.

If the display position is moved to the right by the distance Lmr in thehorizontal direction, an address Whs that is a horizontal data writingstart address in a case in which the display position is not moved isset as a horizontal data writing start address.

Until a period corresponding to (Lh−Lmr−Lcr) has elapsed from the startof the effective image area of an input image, image signals aresequentially obtained by incrementing the horizontal data writing startaddress Whs until a horizontal data writing address (Whs+Lh−Lcr−Lmr) isobtained, and are then sequentially written in the frame memory 30.Subsequently, reduction interpolation processing is performed upon inputimage signals obtained in a period corresponding to the sum of thedistance Lmr and the distance Lcr functioning as the length of acompressed image display area in the horizontal direction. Image signalsare written in the frame memory 30 by incrementing the horizontal datawriting address (Whs+Lh−Lcr−Lmr) by a value obtained by multiplying aposition in the input image by Lcr/(Lcr+Lmr) until a horizontal datawriting address (Whs+Lh−Lmr) is obtained.

However, since a data writing address is an integer in reality, thehorizontal data writing address (Whs+Lh−Lcr−Lmr) is incremented untilthe horizontal data writing address (Whs+Lh−Lmr) is obtained.

At the time of reading of data from the frame memory 30, an address(Rhs−Lmr) obtained by subtracting the distance Lmr from a horizontaldata reading start address Rhs, which is a horizontal data reading startaddress in a case in which the display position is not moved, is set asa horizontal data reading start address. Subsequently, image signalscorresponding to the number of effective pixels Lh are read out byincrementing the horizontal data reading start address (Rhs−Lmr) until ahorizontal data reading address (Rhs+Lh−Lmr) is obtained.

Consequently, after the display position has been moved, a blank imageis displayed in an area of the display screen from the left end thereofto a position apart from the left end by the distance Lmr in thehorizontal direction. A part of the input image 111 in an area from theleft end thereof to the position apart from the left end by the distance(Lh−Lcr−Lmr) in the horizontal direction is displayed without beingcompressed in the normal display area of the display screen from theposition apart from the left end thereof by the distance Lmr in thehorizontal direction to a position apart from the left end by a distance(Lh−Lcr) in the horizontal direction. Furthermore, a part of the image111 in an area from the position apart from the left end thereof by thedistance (Lh−Lcr−Lmr) in the horizontal direction to the position apartfrom the left end by the distance Lh in the horizontal direction iscompressed so as to obtain a compressed image, and the compressed imageis displayed in the compressed image display area of the display screenfrom the position apart from the left end thereof by the distance(Lh−Lcr) in the horizontal direction to the position apart from the leftend by the distance Lh in the horizontal direction. Thus, if an imagedisplay position on a display screen is moved to the right in thehorizontal direction, a part of an image to be extended off the displayscreen is compressed for display so that the part fits within acompressed image display area. As a result, all the informationcontained within the image can be displayed without loss of theinformation.

Third Embodiment

Next, an example illustrated in FIG. 7 will be described. In thisexample, on an image display device having Lh pixels in the horizontaldirection and Lv pixels in the vertical direction, the image 111 havingthe same number of pixels as the image display device is input. Asillustrated using an image 114, a display position is upwardly moved inthe vertical direction by a distance Lmu. The exemplary functionalconfiguration of an image display apparatus according to this embodimentis the same as that of an image display apparatus according to the firstembodiment, and the description thereof will be therefore omitted. Anarea of the image display device from the upper end thereof to aposition apart from the upper end by a distance Lcu in the verticaldirection is set as a compressed image display area.

In this case, a part of the input image 111 in an area from the upperend thereof to a position apart from the upper end by a distance(Lcu+Lmu) in the vertical direction is compressed for display so thatthe part fits within the area of the image display device from the upperend thereof to the position apart from the upper end by the distance Lcuin the vertical direction. Accordingly, in the area of the image displaydevice from the upper end thereof to the position apart from the upperend by the distance Lcu in the vertical direction, an image obtained bycompressing the part of the input image 111 in the area from the upperend thereof to the position apart from the upper end by the distance(Lcu+Lmu) in the vertical direction at a compression ratio ofLcu/(Lcu+Lmu) is displayed.

On the other hand, in an area of the image display device from theposition apart from the upper end thereof by the distance Lcu in thevertical direction to a position apart from the upper end by a distance(Lv−Lmu) in the vertical direction, a part of the input image 111 on thelower side of the position apart from the upper end thereof by thedistance (Lcu+Lmu) in the vertical direction is displayed without beingcompressed. In an area of the image display device on the lower side ofthe position apart from the upper end thereof by the distance (Lv−Lmu)in the vertical direction, for example, a black blank image isdisplayed.

FIG. 8 is a diagram illustrating an example of the time at whichwriting/reading of data in/from the frame memory 30 according to thisembodiment is performed.

Referring to FIG. 8, Vs1 denotes an input vertical synchronizationsignal, Hs1 denotes the input horizontal synchronization signal, DATA1denotes the input image signal, Vs2 denotes an output verticalsynchronization signal, Hs2 denotes the output horizontalsynchronization signal, and DATA2 denotes the output image signal.

If a display position is not moved in the vertical direction, an addressWvs corresponding to the number of horizontal synchronization signalsbetween a falling edge of the input vertical synchronization signal Vs1and the start of the effective image area of an input image is stored inthe frame memory 30 as an input image signal functioning as a verticaldata writing start address. Input image signals corresponding to thenumber of effective lines are written in the frame memory 30 byincrementing the address Wvs until a vertical data writing address(Wvs+Lv) is obtained.

At the time of reading of data from the frame memory 30, based on afalling edge of the output vertical synchronization signal Vs2, avertical data reading start address Rvs is set, and image signalscorresponding to the number of effective lines are read out from theframe memory 30 by incrementing the address Rvs until a vertical datawriting address (Rvs+Lv) is obtained. Consequently, the input image canbe displayed on the entire area of the image display device.

If the display position is upwardly moved by the distance Lmu in thevertical direction, an address Wvs, which is a vertical data writingstart address in a case in which the display position is not moved, isset as a vertical data writing start address. Subsequently, reductioninterpolation processing is performed upon input image signals obtainedin a period corresponding to the sum of the distance Lmu and thedistance Lcu functioning as the length of the compressed image displayarea in the vertical direction. That is, Image signals are written inthe frame memory 30 by incrementing the vertical data writing startaddress Wvs by a value obtained by multiplying a position in the inputimage by Lcu/(Lcu+Lmu) until a vertical data writing address(Wvs+Lmu+Lcu) is obtained.

However, since a data writing address is an integer in reality, avertical data writing address (Wvs+Lmu) is incremented until thevertical data writing address (Wvs+Lmu+Lcu) is obtained. After theperiod corresponding to (Lmu+Lcu) has elapsed from the start of theeffective image area of the input image, image signals are sequentiallyobtained by incrementing the vertical data writing address (Wvs+Lmu+Lcu)until a vertical data writing address (Wvs+Lv) is obtained, and are thensequentially written in the frame memory 30.

At the time of reading of data from the frame memory 30, an address(Rvs+Lmu) obtained by adding the distance Lmu to the vertical datareading start address Rvs, which is a vertical data reading startaddress in a case in which the display position is not moved, is set asa vertical data reading start address. Subsequently, image signalscorresponding to the number of effective lines Lv are read out byincrementing the vertical data reading start address (Rvs+Lmu) until avertical data reading address (Rvs+Lv+Lmu) is obtained.

Consequently, a part of the input image 111 in an area from the upperend thereof to the position apart from the upper end by the distance(Lcu+Lmu) is compressed so as to obtain a compressed image, and thecompressed image is displayed in the compressed image display area ofthe length Lcu in the vertical direction in the display screen. A partof the image 111 in an area from the position apart from the upper endthereof by the distance (Lcu+Lmu) to a position apart from the upper endby the distance Lv is displayed without being compressed in the normaldisplay area of the display screen from the position apart from theupper end thereof by the distance Lcu to the position apart from theupper end by the distance (Lv−Lmu). Furthermore, in an area of thedisplay screen from the position apart from the upper end thereof by thedistance (Lv−Lmu) to the position apart from the upper end by thedistance LV, a blank image is displayed. Thus, if an image displayposition on a display screen is upwardly moved in the verticaldirection, a part of an image to be extended off the display screen iscompressed for display so that the part fits within a compressed imagedisplay area. As a result, all the information contained within theimage can be displayed without loss of the information.

Fourth Embodiment

Next, an example illustrated in FIG. 9 will be described. In thisexample, on an image display device having Lh pixels in the horizontaldirection and Lv pixels in the vertical direction, the image 111 havingthe same number of pixels as the image display device is input. Asillustrated using an image 115, a display position is downwardly movedin the vertical direction by a distance Lmd. The exemplary functionalconfiguration of an image display apparatus according to this embodimentis the same as that of an image display apparatus according to the firstembodiment, and the description thereof will be therefore omitted. Anarea of the image display device from the lower end thereof to aposition apart from the lower end by a distance Lcd in the verticaldirection is set as a compressed image display area.

In this case, a part of the input image 111 in an area from the lowerend thereof to a position apart from the lower end by a distance(Lcd+Lmd) in the vertical direction is compressed for display so thatthe part fits within the area of the image display device from the lowerend thereof to the position apart from the lower end by the distance Lcdin the vertical direction. Accordingly, in the area of the image displaydevice from the lower end thereof to the position apart from the lowerend by the distance Lcd in the vertical direction, an image obtained bycompressing the part of the input image 111 in the area from the lowerend thereof to the position apart from the lower end by the distance(Lcd+Lmd) in the vertical direction at a compression ratio ofLcd/(Lcd+Lmd) is displayed.

On the other hand, in an area of the image display device from theposition apart from the lower end thereof by the distance Lcd in thevertical direction to a position apart from the lower end by a distance(Lv−Lmd) in the vertical direction, a part of the input image 111 on theupper side of the position apart from the lower end thereof by thedistance (Lcd+Lmd) in the vertical direction is displayed without beingcompressed. In an area of the image display device on the upper side ofthe position apart from the lower end thereof by the distance (Lv−Lmd)in the vertical direction, for example, a black blank image isdisplayed.

FIG. 10 is a diagram illustrating an example of the time at whichwriting/reading of data in/from the frame memory 30 according to thisembodiment is performed.

If the display position is downwardly moved in the vertical direction bythe distance Lmd, an address (Wvs−Lmd) obtained by subtracting thedistance Lmd from a vertical data writing start address Wvs, which is avertical data writing start address in a case in which the displayposition is not moved, is set as a vertical data writing start address.

Until a period corresponding to (Lv−Lmd−Lcd) has elapsed from the startof the effective image area of the input image, image signals aresequentially obtained by incrementing the vertical data writing startaddress (Wvs−Lmd) until a vertical data writing address (Wvs+Lv−Lcd−Lmd)is obtained, and are then sequentially written in the frame memory 30.

Subsequently, reduction interpolation processing is performed upon inputimage signals obtained in a period corresponding to the sum of thedistance Lmd and the distance Lcd functioning as the length of thecompressed image display area in the vertical direction. Image signalsare written in the frame memory 30 by incrementing the vertical datawriting address (Wvs+Lv−Lcd−Lmd) by a value obtained by multiplying aposition in the input image by Lcd/(Lcd+Lmd) until a vertical datawriting address (Wvs+Lv−Lmd) is obtained.

However, since a data writing address is an integer in reality, thevertical data writing address (Wvs+Lv−Lcd−Lmd) is incremented until thevertical data writing address (Wvs+Lv−Lmd) is obtained.

At the time of reading of data from the frame memory 30, an address(Rvs−Lmd) obtained by subtracting the distance Lmd from a vertical datareading start address Rvs, which is a vertical data reading startaddress in a case in which the display position is not moved, is set asa vertical data reading start address. Subsequently, image signalscorresponding to the number of effective lines Lv are read out byincrementing the vertical data reading start address (Rvs−Lmd) until avertical data reading address (Rvs+Lv−Lmd) is obtained.

Consequently, in an area of the image display device from the upper endthereof to a position apart from the upper end by the distance Lmd, ablank image is displayed. A part of the input image 111 from the upperend thereof to the position apart from the upper end by the distance(Lv−Lcd−Lmd) is displayed without being compressed in the normal displayarea of the image display device from the position apart from the upperend thereof by the distance Lmd to a position apart from the upper endby the distance (Lv−Lcd). A part of the input image 111 from theposition apart from the upper end thereof by the distance (Lv−Lcd−Lmd)in the vertical direction to a position apart from the upper end by thedistance Lv in the vertical direction is compressed for display so thatthe part fits within the area of the image display device from theposition apart from the upper end thereof by the distance (Lv−Lcd) inthe vertical direction to a position apart from the upper end by thedistance Lv in the vertical direction. Thus, if an image displayposition on a display screen is downwardly moved in the verticaldirection, a part of an image to be extended off the display screen iscompressed for display so that the part fits within a compressed imagedisplay area. As a result, all the information contained within theimage can be displayed without loss of the information.

Fifth Embodiment

FIG. 15 is a block diagram illustrating a hardware configuration of amulti-window system of an image display apparatus according to the fifthembodiment. This system includes at least the following components: acentral processing unit (CPU) 1001, a hard disk drive (HD) 1002, amemory 1003, a mouse 1004, a keyboard 1005, a media drive 1006, and adisplay section 1007. These components are connected to each other via asystem bus 1010. The HD 1002 stores an OS (Operating System) and anapplication program. The mouse 1004 may be another component such as anon-screen digitizer capable of providing information about coordinateson a screen. The display section 1007 is a section for displaying screeninformation generated by the multi-window system, and does not define adisplay device.

FIG. 16 is a block diagram schematically illustrating a configuration ofan image display apparatus according to this embodiment. Referring toFIG. 16, an image display apparatus according to this embodimentincludes a window processing section 1100. The window processing section1100 includes an operation processing unit 1101, a window processingunit 1102, a window condition setting unit 1103, an image compressionunit 1104, and a window image reconstruction unit 1105. The operationprocessing unit 1101 receives input information from the mouse 1004 orthe keyboard 1005, and performs operation processing in accordance withthe input information. Examples of the operation processing includewindow operation processing such as opening, closing, movement, orresizing of a window, and non-window operation processing such as textinput or cursor control performed for application software operated in awindow.

If the window operation processing is performed, the window processingunit 1102 performs window processing in accordance with inputinformation.

FIGS. 17A, 17B, and 17C are diagrams illustrating display examples whena screen according to the fifth embodiment of the present invention ismoved to the left. Referring to FIG. 17A, on a screen 201 included inthe display section 1007, a window 221 is displayed in front of a window211. An example in which the window 211 is moved to the left so as notto overlap with the window 221 will be described. At that time, thewindow processing unit 1102 moves the window 211 to the left andmonitors whether the moved window 211 is in the display area of thescreen 201. The amount of movement of the window may be determined by auser's operation, or may be set in advance. If the amount of movement islarge and the moved window extends off the display area of the screen201 as illustrated in FIG. 17B, the window processing unit 1102 detectsan area extending off the screen 201.

On the other hand, the window condition setting unit 1103 sets acompressed image display area so as to compress an image extending offthe screen 201 and display the compressed image. The compressed imagedisplay area is set using a fixed ratio for each of the number of pixelsLh in the horizontal direction on the screen 201 and the number ofpixels Lv in the vertical direction on the screen 201. This ratio willbe hereinafter referred to as a compressed image display area settingvalue. It is assumed that a compressed image display area setting valuefor a compressed image display area at the left or right end is Hcp, acompressed image display area setting value for a compressed imagedisplay area at the upper or lower end is Vcp, a compressed imagedisplay area at the left or right end is Lch, and a compressed imagedisplay area at the upper or lower end is Lcv. Compressed image displayareas Lch and Lcv are determined as follows.Lch=Lh×Hcp/100Lcv=Lv×Vcp/100

The compressed image display area setting value Hcp for a compressedimage display area at the left end may be different from the compressedimage display area setting value Hcp for a compressed image display areaat the right end. The compressed image display area setting value Vcpfor a compressed image display area at the upper end may be differentfrom the compressed image display area setting value Vcp for acompressed image display area at the lower end.

A compressed image display area may not be set using a ratio for thenumber of pixels Lh in the horizontal direction on the screen 201 or thenumber of pixels Lv in the vertical direction on the screen 201, and maybe directly set using the number of pixels in the horizontal directionor the number of vertical lines on the screen 201.

Alternatively, a compressed image display area may be set using a ratiofor a window 212 that is displayed on the screen 201 without extendingoff the screen 201 after the window 211 has been moved. For example, asillustrated in FIG. 17B, if the window 211 is moved to the left and apart of the window 211 in an area from the left end thereof to aposition apart from the left end by the distance Lml extends off thescreen 201, the number of pixels in the horizontal direction in aremaining part of the window 211 displayed on the screen 201 isrepresented by (Lwh−Lml). At that time, assuming that a compressed imagedisplay area setting ratio is Hwcp and a compressed image display areaat the left end of the screen 201 is Lcl, the compressed image displayarea Lcl is determined by the following equation.Lcl=(Lwh−Lml)×Hwcp/100

An example in which a window is moved to the left has been described.However, the above-described method can also be applied to cases inwhich a window is moved to the right, and a window is upwardly anddownwardly moved.

Furthermore, a compressed image display area may be set in such a mannerthat an object displayed in a non-compressed image display area of thewindow 212, which is a window displayed in the display area of thescreen 201 after the window 211 has been moved, is identified, and thenthe compressed image display area is determined so as not to include theobject or so as to give priority to display of the object.

The above-described setting for the window condition setting unit 1103can be performed using a menu screen displayed as a user interface viathe operation processing unit 1101.

In FIG. 17B, if the window processing unit 1102 detects the areaextending off the display area of the screen 201, the image compressionunit 1104 generates the window 212. More specifically, the imagecompression unit 1104 reduces, based on the setting of the windowcondition setting unit 1103, an area Lml of the window 211 extending offthe display area of the screen 201 and the compressed image display areaLcl so that these areas fit within the compressed image display area Lclillustrated in FIG. 17C. Subsequently, the window image reconstructionunit 1105 reconstructs the moved window image using a compressed imagegenerated by the image compression unit 1104 and an image outside thecompressed image display area, and displays the reconstructed image inthe display section.

Examples of an image compression method include the following methods: amethod of linearly compressing an area Lml extending off the screen 201and a compressed image display area Lcl using, for example, acompression ratio of Lcl/(Lcl+Lml); a method of nonlinearly compressingthese areas by changing a compression ratio so that a higher compressionratio is obtained on the side of one end of the compressed image displayarea; a method of detecting a blank image (for example, a black or whiteimage) included in a part of the window 211 in the area from the leftend thereof to the position apart from the left end by the distance(Lcl+Lml), and setting a high compression ratio for an area includingthe detected blank image or removing the blank image and compressingonly the remaining part excluding the blank image for display; and amethod of identifying objects displayed in the window 211, determiningwhether the moved window 211 extends off the display area of the screen201, sequentially compressing spaces between the objects from one end ofthe display screen in the entire area of the window when it isdetermined that the moved window 211 extends off the display area of thescreen 201, and performing any one of the above-described imagecompression methods when the moved window 211 still extends off thedisplay area of the screen 201 despite the above-described processing.

Next, a process performed by the window processing section 1100 will bedescribed with reference to a flowchart illustrated in FIG. 18. First,in step S101, the window processing unit 1102 determines whether awindow has been moved. If the window has not been moved, the windowprocessing unit 1102 continues to monitor movement of the window. If thewindow has been moved, in step S102, the window processing unit 1102determines whether the moved window extends off the display area of thescreen 201.

If the moved window does not extend off the display area of the screen201, in step S104, the window image reconstruction unit 1105 displaysthe moved window. If the moved window extends off the display area ofthe screen 201, the image compression unit 1104 compresses a part of thewindow extending off the screen 201 and a part of the window in acompressed image display area so that these parts fit within thecompressed image display area so as to generate a compressed image instep S103, and displays a moved window using the compressed image instep S104.

Thus, even if a window is moved and the moved window extends off adisplay screen, all the information contained within the window can bedisplayed without loss of the information.

Sixth Embodiment

In this embodiment, as illustrated in FIGS. 19A and 19B, a borderbetween a compressed image display area and a normal display area isvisible using a slider 300.

The hardware configuration of a multi-window system of an image displayapparatus according to this embodiment and the schematic configurationof the image display apparatus are the same as those according to thefifth embodiment illustrated in FIGS. 15 and 16.

In FIGS. 19A and 19B, a user operates the slider 300 using the mouse1004 so as to change the compressed image display area Lcl, so that awindow 212′ including a compressed image display area Lcl′ is displayedas illustrated in FIG. 19B.

Instead of the slider 300, another method capable of denoting the borderbetween the compressed image display area and the normal display areaand changing the compressed image display area may be used. Accordingly,as illustrated in FIG. 20, a method of displaying a window frame usingdifferent colors may be used.

Next, a process performed by the window processing section 1100according to this embodiment will be described with reference to aflowchart illustrated in FIG. 21.

First, in step S201, the window processing unit 1102 monitors whether acompressed image display area in a window has been changed. If there isno change in the compressed image display area, the process proceeds tostep S101 in which the window processing unit 1102 determines whetherthe window has been moved. If the window has not been moved, the processreturns to step S201 in which the window processing unit 1102 continuesto monitor change in the compressed image display area and movement ofthe window. If it is determined in step S101 that the window has beenmoved, the process from step S102 to step S104 is performed. The processfrom step S102 to step S104 is the same as that according to the fifthembodiment, and the description thereof will be omitted.

If it is determined in step S201 that the compressed image display areahas been changed, the window image reconstruction unit 1105 reconstructsa window image in step S202 based on the change in the compressed imagedisplay area, and displays the reconstructed window image in step S104.

As described previously, the compressed image display area can always bechanged as appropriate based on information displayed in a window.

Another Embodiment

A program stored in an RAM or a ROM included in a computer is executed,whereby each section included in an image display apparatus according toan embodiment of the present invention and each step of an image displaymethod can be achieved. This program and the above-described computerreadable recording medium recording the program are included in thepresent invention.

For example, the present invention can be practiced in the forms of asystem, an apparatus, a method, a program, a recording medium, etc. Morespecifically, the present invention may be applied to a system includinga plurality of devices or an apparatus formed by a single device.

The present invention may be achieved as follows. A software programachieving the functions of the above-described embodiments is directlyor remotely provided for a system or an apparatus. The program code isread out and executed by a computer for the system or apparatus, wherebythe present invention can be achieved.

Accordingly, the present invention can also be achieved by the programcode that is installed on a computer so as to cause the computer toachieve the functional processing of the present invention. That is, acomputer program for achieving the functional processing of the presentinvention is included in the present invention.

Instead of the computer program, other forms such as an object code, aprogram executed by an interpreter, and script data provided for an OSmay be used as long as they have the function of the program.

As a recording medium for providing a program, for example, a flexibledisk, a hard disk, an optical disc, a magneto-optical disk, an MO, aCD-ROM, a CD-R, a CD-RW, a magnetic tape, a nonvolatile memory card, aROM, and a DVD (DVD-ROM or DVD-R) may be used.

A program may be provided by connecting a client computer to an Internethome page via the browser of the client computer, and downloading acomputer program according to an embodiment of the present inventionfrom the home page. Alternatively, a compressed file that has anautomatic installation function may be downloaded to a recording mediumsuch as a hard disk.

In addition, a program according to an embodiment of the presentinvention may be provided in such a manner that a program codeconfiguring the program is divided into a plurality of files, and thedivided files are individually downloaded from different home pages.That is, a WWW server that allows a plurality of users to downloadprogram files required for causing a computer to perform functionalprocessing of the present invention is included in the presentinvention.

A program according to an embodiment of the present invention may beencrypted, be stored on a recording medium such as a CD-ROM, and then beprovided to a user. If the user satisfies predetermined conditions, theuser is allowed to download decryption key information from a home pagevia the Internet. The user can execute the encrypted program using thedownloaded decryption key information, and then install the program on acomputer.

When the computer executes the program, the functions of theabove-described embodiments can be achieved. Furthermore, an OS or thelike running on the computer may perform a part of or all of theprocessing in accordance with the instruction of the program, wherebythe functions of the above-described embodiments can be achieved.

Still furthermore, the program read out from the recording medium may bewritten in a function expansion board inserted into a computer or in amemory provided for a function expansion unit connected to a computer.Subsequently, a CPU included in the function expansion board or thefunction expansion unit performs a part of or all of the processing inaccordance with the instruction of the program, whereby the functions ofthe above-described embodiments can be achieved.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all modifications and equivalent structures and functions.

What is claimed is:
 1. An image display apparatus comprising: a movingunit configured to move a display position of an image displayed on adisplay screen; a setting unit configured to set a compressed imagedisplay area and a non-compressed image display area in the image; and acompression unit configured to, when a non-display area that is notdisplayed on the display screen is created in the image by moving a partof the image outside of the display screen by the moving unit, compressan image of the compressed image display area based on a length of thenon-display area in a moving direction of the image.
 2. The imagedisplay apparatus according to claim 1, wherein, assuming that thelength of the compressed image display area in the moving direction ofthe image is Lc and the length of the non-display area in the movingdirection of the image is Lm, in a case where Lm≧Lc, the compressionunit compresses an image to be displayed in the compressed image displayarea at a compression ratio of Lc/(Lc+Lm).
 3. The image displayapparatus according to claim 1, wherein, assuming that the length of thecompressed image display area in the moving direction of the image is Lcand the length of the non-display area in the moving direction of theimage is Lm, in a case where Lm<Lc, the compression unit compresses animage to be displayed in the compressed image display area at acompression ratio of (Lc−Lm)/Lc.
 4. The image display apparatusaccording to claim 1, wherein the setting unit sets the compressed imagedisplay area based on an amount of movement of the image moved by themoving unit.
 5. The image display apparatus according to claim 1,further comprising a display control unit configured to display a borderbetween the compressed image display area and other areas.
 6. The imagedisplay apparatus according to claim 5, wherein the border is displayedusing a slider, and the compressed image display area is changeable byoperating the slider.
 7. The image display apparatus according to claim5, wherein the border is displayed by changing the color of a frame of awindow on which the image is displayed.
 8. A method comprising: moving adisplay position of an image displayed on a display screen; setting acompressed image display area and a non-compressed image display area inthe image; and compressing, when a non-display area that is notdisplayed on the display screen is created in the image by moving a partof the image outside of the display screen, an image of the compressedimage display area based on a length of the non-display area in a movingdirection of the image.
 9. A non-transitory computer-readable storagemedium storing a computer-executable program for causing a computer toperform a method comprising: moving a display position of an imagedisplayed on a display screen; setting a compressed image display areaand a non-compressed image display area in the image; and compressing,when a non-display area that is not displayed on the display screen iscreated in the image by moving a part of the image outside of thedisplay screen, an image of the compressed image display area based on alength of the non-display area in a moving direction of the image.